Steroid alkali-metal enolates



Patented July 13, 1954 UNITED STATES PATENT OFFICE STEROID ALKALI-METAL ENOLATES I John A. Hogg, Kalamazoo Township, Kalamazoo County, and William P. Schneider, Kalamazoo, Mich., assignors to The Upjohn Company,

Kalamazoo, Mich, a c

orporation of Michigan No Drawing. Application August 21, 1952, Serial No. 305,708

10 Claims. 1 The present invention relates to certain steriod enols and metal enolates thereof and is more par- 2 thereof. Other objects of the present invention will be apparent to those skilled in the art to ticularly concerned with 21-alkoXyoxalyl-3,1lwhich this invention pertains. dihydroxyand 2l-al-koxyoxalyl-3,11-diacyloxy- The novel compounds of the present invention 16,17-oxido-pregnane-20-one and alkali-metal 5 have utility as stable forms of the corresponding enolates thereof. keto acids, keeping well, as convenient solids, for The novel compounds of the present invention long periods of storage. Their water solubility may be represented in their keto form by the makes these compounds readily adaptable for following structural formula: further syntheses, to reactions employing aqueous CH3 0 O media. The corresponding enols, the acids which H H can readily be obtained by hydrolysis and the 21- F acyloxy-3,1l-dihydroxyand 3,11,21-triacyloxy- 0: 16,17 oxido pregnane 20 one compounds as I shown in Examples 1A, 1B and. 1C, furnish valu- R0 able intermediates for the preparation of adrenal CH3 cortical hormones. For example, cortisone acetate may be obtained in the following manner: 304,11 dihydroxy 16,17 oxido 21 acetoxypregnane-ZO-one (Example 1B) is subjected to R0 hydrogen bromide and the resulting lfi-bromol'la-hydroxy derivative is treated with zinc dust h -omine. xidatio of the th and their alkali-metal enolates, by the following 33,3 ,3 ifi, g i g; formula F nane-20-one with chromic acid in acetic acid CH3 OM 0 yields 1'7u-hydroxy-2l-acetoxy-pregnane-3,11,20-

trione, a compound known in the art which may g be converted to cortisone acetate by the procedure of Kritchevsky et al., J. Am. Chem. Soc., '74, 483 "'"ji (1952). R I The novel compounds of the present invention CH3 which are of particular interest are those compounds having the above generic formula, Wherein R is hydrogen or an acyl radical of a hydrocarbon carboxylic acid, preferably such acid con- RTO taining up to eight carbon atoms, inclusive, and R is an alkyl radical, preferably a lower alkyl wherein in the formulae, R. is hydrogen or an acyl radical t ing up to eight carbon atoms, in- 9 group M is an alkali metal and is alkyl and elusive, and the alkali-metal enolates thereof. g t groups t t 3 and 11 positions have Starting materials of the present invention are I either the alpha or beta configuration. 4o l The process of the present invention involves pregnane-2o-ones Which y be p p fI'Om condensation of 3,1l-dihydroxyor 3,11-diacyla l le 3 1 ihyd y- 0r 3,11- i yoxy-16,17-oxido-pregnane-20-one with an alkyl DIGgIIaIIE-ZO-OIIB l e t 1-, J. Biol. Chem., di-ester of oxalic acid in the presence of an 165, 197 (1946) Reichstein et al., Helv. Chim. alkali-metal base to produce 21-a1koxyoxaly1- Acta, 27,1287 (1944)] by bromination, dehydro- 3,11-dihydroxyor 21-all oxyoxalyl-3,ll-diacylbromination and treatment with perbenzoic acid oxy 16,17 oxido pregnane 2O one alkalias S own i Preparation 1 and 2. metal enolate. Treatment with acid produces The configuration of the group at carbon atom the free enol, 21-alkoxyoxalyl-3,ll-dihydroxyor three of the starting material does not influence 21 alkoxyoxalyl 3,11 diacyloxy 16,17 oxidothe course of the reaction in the present invenpregnane-ZO-one. tion. Starting compounds with either an 06- or An object of the present invention is to provide B- configuration of the hydroxy or acyloxy group novel 2l-alkoxyoxalyl-3,1l-dihydroxyand 21- at carbon atom three are equally operative. alkoxyoxalyl 3,11 diacyloxy 16,17 oXido- Since no change in configuration at carbon atom pregnane-ZO-one and the alkali-metal enolates 06 three takes place under the conditions of reaction, the configuration of the product is dependent on the starting material employed.

In carrying out the process of the present in vention, a 3,11-dihydroxyor 3,11-diacyloxy- 16,17-oxido-pregnane-ZO-one is usually dissolved in the allranol corresponding to the allranol which is used in the formation of the selected starting ester of oxalic acid, or in a solvent which is nonreactive under the conditions of reaction, such as, for example, benzene or ether, and mixed with the selected alkyl di-ester of oxalic acid in the presence of an alkali-metal base. The di-esters of oxalic acid. which are preferred in the method of the present invention are lower-alkyl esters containing from one to eight carbon atoms, inclusive. Of these the methyl and ethyl esters are preferred. Alkali-metal bases which may be used include the alkali-metal alkoxides, the alkali metals, the alkali-metal hydrides, sodium amide, triphenymethyl sodium, and others. Of these the sodium and potassium allroxides are preferred. The selected alkali-metal base cataiyses the condensation of the alkyl (ii-ester of oxalic acid with the 3,11-dihydroxyer 3,1l-diacyloxy- 16,17-oxido-pregnane--one and contributes the alkali-metal moiety to the alkali-metal enolate. The alkali-metal alkoxide may be used solventfree, dissolved or suspended in a non-reactive solvent, or in situ in the alkanol in which said alkali-metal alkoxide was formed. When potassium is used, it is usually used as the solution formed by its reaction with tertiary butyl alcohol according to procedure well known in the The resulting reaction mixture is then allowed to stand at a temperature between about zero degrees centigrade and the boiling point of the reaction mixture, preferably at room temperature, for a period of between about one-half hour and about ninety-six hours, usually about one to four hours.

The thus-produced alkali-metal enolate may be separated by the addition of a large volume of an organic solvent in which the alkalinemetal enolate is insoluble, such as, for example, ether, petroleum ether, hexane hydrocarbons and the like. The thus-recovered 21-al1roxyoxalyl-3,1ldihydroxyor 21-alkoxyoxalyl-3,ll-diacyloxy-l6,17 oxido pregnane 20 one alkalimetal enolate is usually obtained as an amorphous stable solid. Alternatively, it may be used, without isolation, as an intermediate in the synthesis of the corresponding 2l-glyoxalic acid, or as an intermediate for the introduction of a 21-hydroxy or 2l-acyloxy group into 3,11- dihydroxyor 3,11-diacyloxy-16,17-oxido-pregnane-ZO-one as described in procedures A and B of Example 1, or as the free enol by treatment of the alkali-metal enolate with a dilute acid, such as hydrochloric acid, sulfuric acid or the like, as described in procedure C of Example l.

The following preparations and examples are given to illustrate the process and products of the present invention and are not to be construed as limiting.

PREPARATION 1.30c,11ocDIHYDROXY-16-PREGNENE- 20-0NE To a solution of 165 milligrams (0.5 millimole) of 3a,l1a-dihydroxypregnane-20-one in 25 milliliters of chloroform was added a solution of eighty milligrams (0.5 millimole) of bromine in five milliliters of chloroform. The addition was done drcpwise and at such a rate that each drop was decolorized before the next drop was added.

When addition was complete, the solvent was removed under reduced pressure and the residue was dissolved in ten milliliters of pyridine. The pyridine solution was then refluxed for eight hours, cooled and poured into water. The aqueous solution was extracted with chloroform and the chloroform solution was washed with dilute sulfuric acid and water. After drying over anhydrous sodium sulfate, the chloroform was evaporated off leaving a pale yellow semi-crystalline residue which was chromatographed over ten grams of Florisil (magnesium silicate). The chrcmatogram was developed with six -milliliter portions of solvent as follows:

Weight of Fraction Solvent Residue Benzene 12.5

. Benzene-ether (9:1) W 8.6

. Benzene-ether (1:1)"... 76.5

Ether 9.0

Acetone 6.2

The eluates were evaporated to dryness and the residue was weighed. Fraction 4, containing 76.5 milligrams, was crystallized from ethyl acetatehexane to yield fifteen milligrams of 3a,l1a-dihydroxy-ld-pregnene-ZO-one; melting point 177.5 to degrees centigrade.

Analysis: Percent calculated for C21H3203I C, 75.86; H, 9.70. Found: C, 75.47; H, 10.08.

PREPARATION 2.3on,11oc-DIHYDROXY-16,17-OXIDO- PREGNANE-QO-ONE Two and one half grams of 30!,11OL-dihYdlOXY- lfil-pregnene-ZO-one were dissolved in fifty milliliters of a benzene solution containing 52 milligrams of perbenzoic acid per milliliter and then allowed to stand in the dark at room temperature for twenty hours. The solution was then diluted with water and repeatedly washed with a five percent sodium hydroxide solution and water. After the benzene solution was dried over anhydrous sodium sulfate, the benzene was removed by vacuum distillation and the solid residue was recrystallized from methanol.

In a manner substantially identical with that of Preparations l and 2, the following compounds are prepared by reaction of the selected 3,11- dihydroxyand 3,1l-diacyloxy16-pregnane-20- one with bromine, followed by pyridine and treatment of the olefinio bond with perbenzoic acid: 38,111: dihydroxy 16,17 oxido pregnane 20- one; 30,11 3 dihydroxy 16,17 oxido pregnanc- 20-one; 33,11 8 dihydroxy 16,17 oxidopregnane-ZO-one and the diformates, diacetates, dipropionates, diisopropionates, dibutyrates, diisobutyrates, divalerates, diisovalerates, dicaproates, dioenanthylates, dicaprylates and dibenzoates of the above diols.

Example 1.S0dium enolate of ZI-ethoxyoraZyl 3a,11u dihydroxy 16,17 oxidepregnane-ZO-one A mixture of 0.59 gram of dry sodium methoxide, twenty milliliters of anhydrous benzene and 2.7 milliliters of ethyl oxalate were stirred until a clear solution was obtained and a solution of 3.48 grams (0.01 mole) of it lic-dihydroxy-16,l7-oxido-pregnane-20-one in 75 milliliters of anhydrous benzene was rapidly added with stirring. Stirring was continued for three hours at room temperature, then 250 milliliters of dry ether was added and the mixture was stirred for an additional 45 minutes. The ivory colored sodium enolate of 21-ethoXyoxalyl-3a,- 11a dihydroxy 16,17 oxido pregnane one thus-precipitated was filtered, washed with ether and dried in a vacuum desiccator at reduced pressure. The presence of a sodium enolate in the structure was verified by the extreme solubility of the product in water and by a positive ferric chloride test for enols as exhibited by the formation of a bright red color when the product was dissolved in aqueous and alcoholic solutions of ferric chloride. The theo retical structure was further verified by infrared and ultraviolet absorption spectra.

A.21GLYOXALIC ACID OF 301,11a-DIHYDROXY- 16,17-OXIDO-PREGNANE-20-ONE Five hundred milligrams of the sodium enolate of 2l-ethoxy-oxalyl-3u,l1a-dihydroxy-16,17-oxido-pregnane-20-one, obtained above, was dissolved in a solution of seventy milligrams of potassium hydroxide in fifteen milliliters of a solution composed of equal parts of water and alcohol, whereafter the whole was heated for fifteen minutes on a steam bath. The cooled solution was then filtered and upon acidification there was slowly deposited a crystalline precipitate of the 2l-glyoxalic acid of EuJIa-dihydroxy 16,17 oxido-pregnane 20 one. Infrared analysis of said compound in solution (chloroform) verified the theoretical structure.

B.2l-ACETOXY-3a,lla-DIHYDROXYJG,17-OXIDO- PREGNANE-20-ONE To a solution of 1792 grams (0.004 mole) of the sodium salt of 2l-ethoxyoxalyl-3a,lla-dihydroxy-16,17-oxido-pregnane-20-one dissolved in milliliters of methanol and cooled in an icebath was added dropwise, with stirring, over a period of approximately one hour, a solution of 1.05 grams (0.004 mole) of iodine dissolved in forty milliliters of methanol while maintaining the reaction temperature between minus fifteen and minus twenty degrees centigrade. The reaction mixture thus produced was stirred for eight minutes at a temperature of about minus fifteen degrees centigrade, whereafter 1.2 milliliters of a 3.4 N methanolic sodium methoxide solution was added thereto. Stirring was continued at zero degrees centigrade for one hour and the thus-produced 3a,1la-dihydroxy-2l-iodo- 16,l7-oxido-pregnane-20-one was precipitated by the dropwise addition of 150 milliliters of water to the reaction mixture while maintaining the reaction temperature at zero degrees centigrade for the hour required to complete the addition. Twenty grams of sodium chloride was then dissolved in the reaction mixture and the product filtered, washed with water, and dried in a vacuum desiccator. The thus-isolated 3a,11a-dihydroxy-21-iodo-l6,l7 oxido-pregnane- 20-one was converted without further purification to 21-acetoxy-8a,11adihydroxy-16,17-oxidopregnane-ZO-one as shown below.

To a freshly prepared mixture composed of twenty grams of potassium bicarbonate, twelve grams of glacial acetic acid and ten milliliters of acetone was added the 306,1ld-dihYd1'OXY-2liodo-l6,l7-oxido-pregnane-20-one obtained above dissolved in 100 milliliters of acetone. The mixture was heated under refluxing conditions for one hour whereafter the mixture was kept at room temperature for 2.5 days. The inorganic solids were removed by filtration and washed with 25 milliliters of acetone. The filtrate and wash were combined and the acetone removed by evaporation. The residue was extracted with three fifty-milliliter portions of warm ethyl acetate which were then combined, washed with a dilute sodium thiosulfate solution and water, and finally dried over anhydrous sodium sulfate. The dry ethyl acetate was distilled in vacuo and the residue was dissolved in a small portion of benzene and chromatographed. Infrared analysis confirmed the structure of the 21-acetoxy- 30,11a dihydroxy 16,17 oxido pregnane-ZO- one thus obtained.

OXIDO-PREGNANE-20-ONE Five hundred milligrams of the sodium enolate of 21-ethoxy-oxalyl-3u,11u-dihydroxy-16,17- oxido-pregnane-ZO-one were dissolved and suspended in twenty milliliters of water. Ten milliliters of ten percent hydrochloric acid were added and the precipitate which separated collected on filter paper, washed with water and dried in a vacuum desiccator over Drierite (anhydrous calcium sulfate). Infrared analysis confirmed the structure of the 2l-ethoxyoxalyl-3u,lla-dihydroxy-16,17-oxido-pregnane-20-one.

Example 2.Sodium enolate 0 f 21 -methoa:yoxaZyZ-3u,1 1 wdihydroxy-l 6,1 7 -oa:ido-pregnane- 20 -one Using essentially the procedure described in Example 1, 3a,lla-dihydroxy-16,17-oxido-pregnane-20-one is converted to the sodium enolate of 21 methoxyoxalyl 30:,110: dihydroxy 16,17- oxido-pregnane-ZO-one by reaction with methyl oxalate and sodium in absolute methanol. The resulting sodium enolate is converted, as with the 21-glyoxalic acid of 3a,l1a-dihydroxy-16,17- oxido pregnane 20 one, 21 acetoxy 30,1ludihydroxy-l6,l7-oxidoregnane-20-one, and 21- methoxyoxalyl-3p,11u dihydroxy 16,17 oxidopregnane-20-one according to the procedure of Example 1A, 1B, and 10.

Example 3.Sodium enolate of 21 -methoznyoa3- al Z 35,110; dihydroccy 16,17 oxido pregmme-ZO-one Using essentially the procedure described in Example 1, 3,8,1la-dihydroxy16,17-oxido-pregnane-20-one is converted to the sodium enolate of 21 methoxyoxalyl 36,110 dihydroxy- 16,l7-oxido-pregnane-20-one by reaction with methyl oxalate and sodium in absolute methanol. The resulting sodium enolate is converted, as with the 3a,l1 x-dihydroxy compound, to the 2l-glyoxalic acid of 3fi,11a-dihydroxy-16,l7- oxido-pregnane-ZO-one, 2l-acetoxy-3fi,11d-dihydroxy-16,17--oxido-pregnane-20-one, and 21- methoxyoxalyl 35,110; dihydroxy 16,17-oxidopregnane-20-one according to the procedure of Example 1A, 1B, and 10.

Example 4.-Potassium enolate of ZI-ethomyoralyl 35,115 dihydroxy 16,17 orm'dopregnane-ZO-one Using essentially the procedure described in Example 1, 35,1I S-dihydroXy-16,17-oxido-pregnane-20-one is converted to the potassium enolate of 2I-ethoxyoxalyl-35,llfl-dihydroxy-16,17- oxido-pregnane-ZG-one by reaction with ethyl oxalate and potassium in tertiary butyl alcohol. The resulting potassium enolate is converted, as with the corresponding sodium enolate, to the 21- glyoxalic acid of 35,11,8-dihydroxy-16,l7-oxido pregnane 20 one, 21 acetoxy 35,115 dihydroxy 16,17 oxide pregnane 20 one, and 21 ethoxyoxalyl 3,8,11,6 dihydroxy- 16,17 oxido pregnane 20 one according to the procedure of Example 1A, 1B, and 10.

Example 5.Potassium enolate of ZI-ethoazyomaiyl 304,11 diacetomy 16,17 oxideqiregnane 20 one Using essentially the procedure described in Example 1, 3a,lla-diacetoxy-16,1'l-oxido-pregnane-20-one is converted to the potassium enolate of 2l-ethoXyoxalyl-3a,l1a-diacetoXy--16,1'l oxido-pregnane-ZO-one by reaction with ethyl oxalate and potassium in tertiary butyl alcohol.

In a manner substantially identical with that of Examples 1 through 5, the following compounds are prepared by reaction of the selected 3,11-dihydroxyor 3,1l-cliacyloxy-16,17-oxido-pregnane-ZO-one with the appropriate alkyl oxalate and sodium or potassium alkoaide in an alkanol or non-reactive solvent medium: sodium enolate of 21 propoxyoxalyl-iiadla-dihydroXy-16J7-oX- ido-pregnane-20one, sodium enolate of 21-butoxyoxalyl- 3m,lladihydroxy-l6,1'7- oxidopre nane-20-one, sodium enolate of 21-amyloxyoxalyl-3a,1la-dihydroxy-16,17- oxido-pregnane-ZO- one, sodium enolate of 21-heXyloxyoXalyl-3u,lludihydroxy-16,17oxido-pregnane-20-one, sodium enolate of 2l-heptyloXyoxalyl-3a,lla-dihydroxy- 16,17-Xid0-pregnane-20-one, sodium enolate of 2l-octyloXyoxalyl-3u,11- dihydroxy-16,17-oxidopregnane-ZO-one, the corresponding 3B,].1m isomers, the 3u,1l;3 and the 3 3,115 isomers, the potassium analogues of these and like compounds and specifically the esters of the 3,110c-di01S above, such as the diformate, diacetate, dipropionate, dibutyrate and diisobutyrate, divalerate and diisovalerate, dicaproate, dioenanthylate, dicaprylate and dibenzoate, and similar related compounds.

It is to be understood that the invention is not to be limited to the exact details or exact compounds shown and described as obvious modifications and equivalents will be apparent to one skilled in the art, and the invention is therefore to be limited only by the scope of the appended claims.

We claim:

1. A compound selected from the group consisting of (l) 2l-lower-alkoxyoxalyl-3,ll-dihydroxy-l6,1'7-oxidopregnane-20-one, represented by the following formula:

OH; (H)

(2) alkali-metal enolate thereof, (3) .21-loweralk-oxyoxalyl 3,11-diacy1oxy 16,1'7-- oxidopregnane-20-one, represented by the following formula:

Ac-O

3. The potassium enolate of 21-lower-alkoxyoxalyl-3,ll-dihydroxy-16,1'7-oxido-pregnane- 20-one.

4. The sodium enolate of 2l-lower-alkoxyoxalyl- 3,11adiacyloxy- 16,1'7- oxido-pregnane-20- one, wherein the acyloxy group is of the formula AcO, Ac being the radical of a hydrocarbon carboxylic acid containing from one to eight carbon atoms, inclusive.

5. The potassium enolate of 21-lower-alkoxyoxalyi-3,1lu-diacyloxy-l6,17-oXido-pregnane-20- one, wherein the acyloxy group is of the formula AcO, Ac being the radical or" a hydrocarbon carboxylic acid containing from one to eight carbon atoms, inclusive.

6. The sodium enolate of ZI-methoxyoxalyl- 3a,llu-dihydroxy-16,1'1-oXido-pregnane-20one.

7. The sodium enolate of 2l-eth0Xyoxalyl-3a,- lla-dihydroxy-16,1'7-oxido-pregnane-20-one.

8. 21- etlroxyoxalyl 3:1,110: dihydroxy- 16,17- oxido-pregnane-flU-one 9. The potassium enolate of 21-ethoxyoxaly1- 3oz,1loc-diaOetOXY-16,17-0Xid0-pl'6gllfin6-20-OI1B.

10. The sodium enolate of 21-methoxyoxalyl- 3fi,lla-dihydroxyl6,l'I-oxido-pregnane-ZO-one.

No references cited. 

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF (1) 21-LOWER-ALKOXYOXALYL-3,11-DIHYDROXY-16,17-OXIDOPREGNANE-20-ONE, REPRESENTED BY THE FOLLOWING FORMULA: 